<?php

/**
* Project:     MagpieRSS: a simple RSS integration tool
* File:        rss_parse.inc  - parse an RSS or Atom feed
*               return as a simple object.
*
* Handles RSS 0.9x, RSS 2.0, RSS 1.0, and Atom 0.3
*
* The lastest version of MagpieRSS can be obtained from:
* http://magpierss.sourceforge.net
*
* For questions, help, comments, discussion, etc., please join the
* Magpie mailing list:
* magpierss-general@lists.sourceforge.net
*
* @author           Kellan Elliott-McCrea <kellan@protest.net>
* @Updated by       Gavin Spearhead
* @version          0.7a
* @license          GPL
*
*/

if (!defined('ORIGINAL_PAGE')) die('This file cannot be accessed directly.');


define('RSS', 'RSS');
define('ATOM', 'Atom');


function concat (&$str1, $str2='')
{
	if (!isset($str1) ) 
		$str1 = '';
	$str1 .= $str2;
}


/**
* Hybrid parser, and object, takes RSS as a string and returns a simple object.
*
* see: rss_fetch.inc for a simpler interface with integrated caching support
*
*/
class MagpieRSS {
	private $parser;

	public $current_item   = array();  // item currently being parsed
	public $items          = array();  // collection of parsed items
	public $channel        = array();  // hash of channel fields
	public $textinput      = array();
	public $image          = array();
	public $feed_type;
	public $feed_version;
	public $encoding       = '';       // output encoding of parsed rss
	public $_source_encoding = '';     // only set if we have to parse xml prolog

	// define some constants

	static private $_CONTENT_CONSTRUCTS = array('content', 'summary', 'info', 'title', 'tagline', 'copyright');
	static private $_KNOWN_ENCODINGS    = array('UTF-8', 'US-ASCII', 'ISO-8859-1');

	// parser variables, useless if you're not a parser, treat as private
	public $stack              = array(); // parser stack
	public $inchannel          = FALSE;
	public $initem             = FALSE;
	public $incontent          = FALSE; // if in Atom <content mode="xml"> field 
	public $intextinput        = FALSE;
	public $inimage            = FALSE;
	public $current_namespace  = FALSE;
	public $last_modified      = 0;

	/**
	 *  Set up XML parser, parse source, and return populated RSS object..
	 *   
	 *  @param string $source           string containing the RSS to be parsed
	 *
	 *  NOTE:  Probably a good idea to leave the encoding options alone unless
	 *         you know what you're doing as PHP's character set support is
	 *         a little weird.
	 *
	 *  NOTE:  A lot of this is unnecessary but harmless with PHP5 
	 *
	 *
	 *  @param string $output_encoding  output the parsed RSS in this character 
	 *                                  set defaults to ISO-8859-1 as this is PHP's
	 *                                  default.
	 *
	 *                                  NOTE: might be changed to UTF-8 in future
	 *                                  versions.
	 *                               
	 *  @param string $input_encoding   the character set of the incoming RSS source. 
	 *                                  Leave blank and Magpie will try to figure it
	 *                                  out.
	 *                                  
	 *                                   
	 *  @param bool   $detect_encoding  if false Magpie won't attempt to detect
	 *                                  source encoding. (caveat emptor)
	 *
	 */
	function __construct ($source, $output_encoding='ISO-8859-1', $input_encoding=NULL, $detect_encoding=TRUE) 
	{   
		$source = $this->create_parser($source, $output_encoding, $input_encoding, $detect_encoding);

		if (!is_resource($this->parser)) 
			throw new exception('Failed to create an instance of the XML parser.', ERR_MAGPIE_FAILED );

		# pass in parser, and a reference to this object
		# setup handlers
		#
		xml_set_object( $this->parser, $this );
		xml_set_element_handler($this->parser, 'feed_start_element', 'feed_end_element' );
		xml_set_character_data_handler( $this->parser, 'feed_cdata' ); 

		$status = xml_parse( $this->parser, $source );

		if (! $status ) {
			$errorcode = xml_get_error_code( $this->parser );
			if ( $errorcode != XML_ERROR_NONE ) {
				$xml_error = xml_error_string( $errorcode );
				$error_line = xml_get_current_line_number($this->parser);
				$error_col = xml_get_current_column_number($this->parser);
				$errormsg = "$xml_error at line $error_line, column $error_col";

				throw new exception( $errormsg, ERR_MAGPIE_FAILED);
			}
		}

		xml_parser_free( $this->parser );

		$this->normalize();
	}

	function feed_start_element($p, $element, array &$attrs) 
	{
		$el = $element = strtolower($element);
		$attrs = array_change_key_case($attrs, CASE_LOWER);

		// check for a namespace, and split if found
		$ns = FALSE;
		if ( strpos( $element, ':' ) ) {
			list($ns, $el) = explode( ':', $element, 2); 
		}
		if ( $ns && $ns != 'rdf' ) {
			$this->current_namespace = $ns;
		}

		# if feed type isn't set, then this is first element of feed
		# identify feed from root element
		#
		if (!isset($this->feed_type) ) {
			if ( $el == 'rdf' ) {
				$this->feed_type = RSS;
				$this->feed_version = '1.0';
			} elseif ( $el == 'rss' ) {
				$this->feed_type = RSS;
				$this->feed_version = $attrs['version'];
			} elseif ( $el == 'feed' ) {
				$this->feed_type = ATOM;
				$this->feed_version = $attrs['version'];
				$this->inchannel = true;
			}
			return;
		}

		if ( $el == 'channel' ) {
			$this->inchannel = TRUE;
		} elseif ($el == 'item' || $el == 'entry' ) {
			$this->initem = TRUE;
			if ( isset($attrs['rdf:about']) ) {
				$this->current_item['about'] = $attrs['rdf:about']; 
			}
		}

		// if we're in the default namespace of an RSS feed,
		//  record textinput or image fields
		elseif ( $this->feed_type == RSS && 
			$this->current_namespace == '' && 
			$el == 'textinput' ) {
			$this->intextinput = TRUE;
		} elseif ( $this->feed_type == RSS && 
			$this->current_namespace == '' && 
			$el == 'image' ) {
			$this->inimage = TRUE;
		}

		# handle atom content constructs
		elseif ( $this->feed_type == ATOM && in_array($el, self::$CONTENT_CONSTRUCTS) )
		{
			// avoid clashing w/ RSS mod_content
			if ($el == 'content' ) 
				$el = 'atom_content';

			$this->incontent = $el;
		}

		// if inside an Atom content construct (e.g. content or summary) field treat tags as text
		elseif ($this->feed_type == ATOM && $this->incontent ) {
			// if tags are inlined, then flatten
			$attrs_str = join(' ', 
				array_map('map_attrs', 
				array_keys($attrs), 
				array_values($attrs) ) );

			$this->append_content( "<$element $attrs_str>"  );
			array_unshift( $this->stack, $el );
		}

		// Atom support many links per containging element.
		// Magpie treats link elements of type rel='alternate'
		// as being equivalent to RSS's simple link element.
		//
		elseif ($this->feed_type == ATOM && $el == 'link' ) {
			if ( isset($attrs['rel']) && $attrs['rel'] == 'alternate' ) {
				$link_el = 'link'; }
			else 
				$link_el = 'link_' . $attrs['rel'];
			
			$this->append($link_el, $attrs['href']);
		} else // set stack[0] to current element
			array_unshift($this->stack, $el);
	}


	function feed_cdata ($p, $text) {
		if ($this->feed_type == ATOM && $this->incontent) {
			$this->append_content( $text );
		} else {
			$current_el = join('_', array_reverse($this->stack));
			$this->append($current_el, $text);
		}
	}

	function feed_end_element ($p, $el) 
	{
		$el = strtolower($el);

		if ( $el == 'item' || $el == 'entry' ) {
			$this->items[] = $this->current_item;
			$this->current_item = array();
			$this->initem = FALSE;
		} elseif ($this->feed_type == RSS && $this->current_namespace == '' && $el == 'textinput' ) {
			$this->intextinput = FALSE;
		} elseif ($this->feed_type == RSS && $this->current_namespace == '' && $el == 'image' ) {
			$this->inimage = FALSE;
		} elseif ($this->feed_type == ATOM && in_array($el, $this->_CONTENT_CONSTRUCTS) ) {   
			$this->incontent = FALSE;
		} elseif ($el == 'channel' || $el == 'feed' ) {
			$this->inchannel = FALSE;
		} elseif ($this->feed_type == ATOM && $this->incontent  ) {
			// balance tags properly
			// note:  i don't think this is actually neccessary
			if ( $this->stack[0] == $el ) {
				$this->append_content("</$el>");
			} else {
				$this->append_content("<$el />");
			}

			array_shift( $this->stack );
		} else {
			array_shift( $this->stack );
		}

		$this->current_namespace = FALSE;
	}

	function append_content($text) 
	{
		if ( $this->initem ) {
			concat( $this->current_item[ $this->incontent ], $text );
		} elseif ( $this->inchannel ) {
			concat( $this->channel[ $this->incontent ], $text );
		}
	}

	// smart append - field and namespace aware
	function append($el, $text) 
	{
		if (!$el) 
			return;
		
		if ( $this->current_namespace ) {
			if ( $this->initem ) {
				concat( $this->current_item[ $this->current_namespace ][ $el ], $text);
			} elseif ($this->inchannel) {
				concat( $this->channel[ $this->current_namespace][ $el ], $text );
			} elseif ($this->intextinput) {
				concat( $this->textinput[ $this->current_namespace][ $el ], $text );
			} elseif ($this->inimage) {
				concat( $this->image[ $this->current_namespace ][ $el ], $text );
			}
		} else {
			if ( $this->initem ) {
				concat( $this->current_item[ $el ], $text);
			} elseif ($this->intextinput) {
				concat( $this->textinput[ $el ], $text );
			} elseif ($this->inimage) {
				concat( $this->image[ $el ], $text );
			} elseif ($this->inchannel) {
				concat( $this->channel[ $el ], $text );
			}
		}
	}

	function normalize () 
	{
		// if atom populate rss fields
		if ( $this->is_atom() ) {
			$this->channel['description'] = $this->channel['tagline'];
			for ( $i = 0; $i < count($this->items); $i++) {
				$item = $this->items[$i];
				if ( isset($item['summary']) )
					$item['description'] = $item['summary'];
				if ( isset($item['atom_content']))
					$item['content']['encoded'] = $item['atom_content'];

				$atom_date = (isset($item['issued']) ) ? $item['issued'] : $item['modified'];
				if ( $atom_date ) {
					$epoch = @strtotime($atom_date);
					if ($epoch and $epoch > 0) {
						$item['date_timestamp'] = $epoch;
					}
				}

				$this->items[$i] = $item;
			}       
		}
		elseif ( $this->is_rss() ) {
			$this->channel['tagline'] = $this->channel['description'];
			for ( $i = 0; $i < count($this->items); $i++) {
				$item = $this->items[$i];
				if ( isset($item['description']))
					$item['summary'] = $item['description'];
				if ( isset($item['content']['encoded'] ) )
					$item['atom_content'] = $item['content']['encoded'];

				if ( $this->is_rss() == '1.0' && isset($item['dc']['date']) ) {
					$epoch = @strtotime($item['dc']['date']);
					if ($epoch and $epoch > 0) 
						$item['date_timestamp'] = $epoch;
				}
				elseif ( isset($item['pubdate']) ) {
					$epoch = @strtotime($item['pubdate']);
					if ($epoch > 0) 
						$item['date_timestamp'] = $epoch;
				}

				$this->items[$i] = $item;
			}
		}
	}

	function is_rss () 
	{
		if ( $this->feed_type == RSS ) 
			return $this->feed_version; 
		else 
			return FALSE;
	}

	function is_atom() 
	{
		if ( $this->feed_type == ATOM ) 
			return $this->feed_version;
		else 
			return FALSE;
	}

	/**
	 * return XML parser, and possibly re-encoded source
	 *
	 */
	function create_parser($source, $out_enc, $in_enc, $detect) {
		if(!$detect && $in_enc) 
			$this->parser = xml_parser_create($in_enc);
		else 
			$this->parser = xml_parser_create('');

		if ($out_enc) {
			$this->encoding = $out_enc;
			xml_parser_set_option($this->parser, XML_OPTION_TARGET_ENCODING, $out_enc);
		}

		return $source;
	}

	function known_encoding($enc) {
		$enc = strtoupper($enc);
		if ( in_array($enc, self::$_KNOWN_ENCODINGS) ) 
			return $enc;
		 else 
			return FALSE;
	}


} // end class RSS

function map_attrs($k, $v) {
	return "$k=\"$v\"";
}


?>
